The present invention relates to a slip-controlled brake system for automotive vehicles comprising a braking pressure generator with a master cylinder and a brake power booster connected to an auxiliary-energy supply system, wherein at least two brake circuits are provided, one thereof being connected to a fast-fill cylinder.
In patent application No. P 350,870.99, there is provision of a fast-fill cylinder enabling an abrupt change in ratio if the hydraulic brake power booster or the auxiliary-energy supply fails and it is only the pedal force of the vehicle operator that is left available for the braking action. Although the fast-fill cylinder in this brake system is inserted in the static brake circuit, it bears the disadvantage that exact positioning of the booster piston is a problem.
It is an object of the present invention to provide a brake system of the type described which, on booster failure, operates with a reduced master brake cylinder surface and which affords exact positioning of the brake pedal during the introduction of pressure fluid from the hydraulic booster into the brake circuits (dynamic fluid flow during braking pressure control).